This invention relates to a method and machine for sewing together the outer marginal edge portions of adjacent mattress outer covers with which a cushion is wrapped.
As well known in the art, a mattress consists of a cushion constituting an inner structure and an outer covering which wraps the cushion. Conventionally, the outer covering consists of a few outer covers i.e., a pair of upper and lower outer covers and a gusset covering the side of the cushion, all of which three-dimensionally wrap the cushion in all sides. Where the cushion is wrapped with the outer covers, one outer cover and gusset are sewn together at their adjacent outer marginal edge portions into an open box-like configuration. A mattress is formed by wrapping a cushion with the box-like outer cover while disposing another outer cover under the open end of the box-like outer cover and sewing together the outer marginal edge portions of the adjacent outer covers. The outer covering is tightly wrapped over the cushion in all sides without any sagging and it must be made somewhat smaller in size than the outer dimension of the cushion. When the sewing is finally effected, the outer marginal edge portions of the adjacent outer covers are sewn together while fairly strongly compressing the cushion with the elbow of the sewer. In the prior art, therefore, a high skill is required in sewing together the outer marginal edge portions of the adjacent outer covers and, in addition, it is difficult to uniformly compress the cushion and it is impossible, therefore, to manufacture mattress on a quantity production basis.